Question for Parisse about CAS floating point

[parisse]

To make things clearer, inside the CAS you have exact rationals to represent rationals, therefore there is no need to use floating point numbers to represent only a few rationals (included in the rationals that have a power of 2 as denominator), unlike for applications that do not have exact representation for rationals. Inside a CAS, floating point means approx data. And that's how they are used for in the vast majority of scientific computations.